The brain and spinal cord are enclosed and protected by the meninges; tough and fibrous tissues comprising the dura mater and pia mater. Developmentally, these tissues form partly from the neural crest; a class of highly migratory and plastic cells that also form several diverse tissue types, such as bone, cartilage, muscle, gut, adrenal glands, etc. The dura mater has been shown to regulate bone formation in the developing skull through tissue interactions mediated by growth factors originating in the dura (L. A. Opperman et al., “Tissue interactions with underlying dura mater inhibit osseous obliteration of developing cranial sutures,” Dev. Dynamics, 198(4):312-322 (1993)). During skull regeneration in humans and animals whose heads are still growing, the bone and other connective tissues of the skull are formed from cellular precursors in the dura (FIG. 1; D. B. Drake et al., “Calvarial deformity regeneration following subtotal craniectomy for craniosynostosis: a case report and theoretical implications,” J. Craniofacial Surg., 4(2):85-90 (1993)).
Moreover, there is extensive interest in developing methods for using pluripotential stem cell populations for a wide variety of potential therapeutic applications, including delivery of therapeutic genes, correction of gene defects, replacement/augmentation of existing dysfunctional cell populations (e.g., dopaminergic neurons in Parkinsons Disease), and generation of organs/tissues for surgical repair/replacement. However, existing methods in the field have a number of major limitations that relate to obtaining purified populations of the desired cell types from pluripotent stem cells. By way of example, embryonic stem cells pose interesting possibilities as several studies show that these cells are pluripotent, however, the use of these cells is mired in ethical and political considerations. It is therefore likely that this technology will not be available for use in the near future.
There is a need in the art for a stem cell population that obviates the limitations of currently available stem cells; thereby enabling further research in this field, and also the therapeutic, clinical use of stem cells in various aspects of biomedicine. The present invention is directed to such a novel stem cell population, which is isolated from meningeal tissues. This stem cell population has properties that provide significant advantages over the stem cells currently available.